וּבְכָ֥ה וּֽבְעַמְּךָ֖ וּבְכָל־עֲבָדֶ֑יךָ יַעֲל֖וּ הַֽצְפַרְדְּעִֽים׃
And the frogs shall come up both upon thee, and upon thy people, and upon all thy servants.’
Rashi on Exodus
ובכה ובעמך AND UPON (or in) THEE AND THY PEOPLE [SHALL THE FROGS COME] — they made their way right into their bodies and crowed (Exodus Rabbah 10:3).
Rabbeinu Bahya
ובכה ובעמך, “against you as well as against your people.” The unusual letter ה at the end of the word ובך “and against you,” indicates that every one of the ten plagues was subdivided into 5 plagues [compare Haggadah shel Pessach Rabbi Yossi Hagalilee].
Siftei Chakhamim
They would enter and croak. מקרקרין means crying out and making noise.